An unexpectedly defensive President Obama yesterday dared Capitol Hill Republicans to “go after me” on the Benghazi consulate intelligence debacle.

Well, he can’t say he didn’t ask for it.

“Whoever was at fault must be held responsible, and most importantly the president, who is commander-in-chief,” said Sen. John McCain, as he called for creation of a special Senate investigating panel.

Indeed, he charged, the president either has shown “colossal incompetence” or has “engaged in a coverup” — adding, “The president did not tell the American people the truth.”

Also, during his first news conference in eight months, Obama blasted McCain and Sen. Lindsay Graham for vowing to oppose UN Ambassador Susan Rice if she’s nominated to be secretary of state.

“And I’m happy to have that discussion,” a bellicose Obama responded.

Well, good.

Here’s hoping the debate begins with a dissection of Obama’s admission that Rice’s dishonest post-Benghazi appearances on TV talk shows were made “at the request of the White House.”

That’s when she repeated the already-discredited line that Benghazi was a “spontaneous” attack fueled by an Internet video.

The president accused McCain and Graham of seeking to “besmirch her reputation” — which is a little silly, given the job she herself has done of it.

Senators have an obligation to hold to account any top official who lies to the country — or who serves as a transmission line for false information.

All this eclipsed news that former CIA Director David Petraeus has reversed course and agreed to testify under oath about his undercover post-attack fact-finding trip to Benghazi.

The retired four-star general also blamed Benghazi on the video — in front of Congress, no less! — although he certainly had to have known better.

This time, he will be under oath, and lawmakers need to wring the full truth out of him. Of course, whether his own personal drama played any role in his earlier, misleading, testimony must be explored, as well.

Benghazi is important in its own right — by all accounts it represented a grave US intelligence failure.

Equally critical is the likelihood — near certainty, actually — that the murders of four Americans were politicized to serve Obama’s re-election campaign.